zfs very poor performance compared to ufs due to lack of cache?

[Andriy Gapon]

on 08/09/2010 11:48 Kostik Belousov said the following:
> On Wed, Sep 08, 2010 at 10:19:48AM +0300, Andriy Gapon wrote:
>> on 07/09/2010 10:26 Andriy Gapon said the following:
>>> Interesting.  I briefly looked at the code in mappedread(), zfs_vnops.c, and I
>>> have a VM question.
>>> Shouldn't we mark the corresponding page bits as valid after reading data into
>>> the page?
>>> I specifically speak of the block that starts with the following line:
>>> } else if (m != NULL && uio->uio_segflg == UIO_NOCOPY) {
>>> I am taking mdstart_swap as an example and it does m->valid = VM_PAGE_BITS_ALL.
>>>
>>
>> I've chatted with and conclusion seems to be that vm_page_set_validclean() call
>> should be added at the end of the block.
>>
>> Perhaps, something like this:
>>
>> --- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
>> +++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vnops.c
>> @@ -500,6 +500,7 @@ again:
>>  				sched_unpin();
>>  			}
>>  			VM_OBJECT_LOCK(obj);
>> +			vm_page_set_validclean(m, off, bytes);
> Only if error == 0, perhaps ?

Yes, I agree, thanks!

-- 
Andriy Gapon